I've been trying to convince SqueezeBox folks to not use digital attenuation and ironically, in defense that it's ok to attenuate digitally someone pointed out this old test that proves digital attenuation is very costly.

They seem have difficult time over there interpreting test results. Or even reading the designers comments they keep referring to on the topic. Which he sums up in 1 sentence. "it does NOT mean that those first 8 bits of attenuation are "free"".

Any way this test is on the SqueezeBox's DAC itself. It's supposed to have a "24Bit DAC".

The Volume scale at the time of this test is 1.25dB per step.

So

Volume 40 is 00.0dB attenuation. About 0-Bits. Close to 96dB Dynamic Range no loss.
Volume 30 is 12.5dB attenuation. About 2-Bits. Drops to 88dB Dynamic Range 1.25 bits lost
Volume 20 is 25.0dB attenuation. About 4-Bits. Drops to 75dB Dynamic Range almost 4 bits lost

If the DAC was Perfect for even for 20Bits. Those should all read close to 96dB.

http://mysite.verizon.net/forumwebspace/RightMark/Test%20Reports/Volume.htm

- Fiddler (IMHO)

If you think listening to music is fun, try learning an instrument.
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